Solution processed bismuth sulfide nanowire array core/silver shuffle shell solar cells

Low bandgap inorganic semiconductor nanowires have served as building blocks in solution processed solar cells to improve their power conversion capacity and reduce fabrication cost. In this work, we first reported bismuth sulfide nanowire arrays grown from colloidal seeds on a transparent conductive substrate via mild aqueous chemistry and demonstrated a novel core–shell nanowire architecture to enhance the photovoltaic performances of hybrid solar cells. We found that the bismuth sulfide nanowire core/silver sulfide shell structure reduces the interfacial charge recombination between the core and a hole transporter layer and enables efficient charge separation in a type-II core–shell heterojunction. The bismuth sulfide nanowire core/silver sulfide shell combined with 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) reached solar-to-electricity power conversion efficiency of 2.5%, advancing the field of solution processed solar cells based on environmentally friendly metal chalcogenide semiconductors.